The present invention relates to chroma keying, and more particularly to a graphic display for chroma keyer control which is intuitive for an operator.
A long standing problem with chroma keyers is how to distinguish different portions of a scene. An operator starts with a foreground scene that he wants to chroma key into a more or less unrelated background scene. But the foreground scene has a background portion and a foreground portion. The foreground portion is the part that is to be keyed into the new background scene. The background portion is usually a flat matte color, such as blue, which the chroma keyer operates on. As a result chroma keyers are complex functions with many controls. Such controls may be difficult to operate from an operator's perspective. The controls typically include knobs that are simply labeled by function, and which may include a numerical display of knob value. In a few cases a bar graph representation of the knob value may be displayed. However these controls are not very intuitive. The operator requires considerable skill to translate information displayed in this manner to develop an understanding of what the chroma keyer is doing.
What is desired is an intuitive display for conveying to an operator information about what a chroma keyer is doing as control knobs are manipulated.